Analysis of Turbulent Near Wakes
Author: A. Prabhu
Publisher:
Published: 1983
Total Pages: 46
ISBN-13:
DOWNLOAD EBOOKThis report is concerned with the analytical treatment of the flow in the near wake behind sharp trailing edges with a fully-developed zero-pressure gradient turbulent boundary layer just upstream of the trailing edge. The three cases considered are the flows behind two-dimensional, axisymmetric and infinitely-yawed sharp trailing edges. The principal limits that govern the near wake seem to be Square root of C sub f as it approaches 0 and Square root of C sub f x R sub sigma as it approaches infinity, where C sub f and R sub sigma are the skin friction in the upstream boundary layer and the Reynolds number based on shear layer thickness, respectively. This is the same limit as that for the local asymptotic analysis of a fully-developed turbulent boundary layer under zero pressure gradient at large Reynolds numbers. These limiting conditions lead to the governing equations for the inner and outer near-wake and a logarithmic variation of the velocity in the overlapping region. It is argued that the same limiting conditions also lead to a logarithmic variation of the centerline velocity in the near wake. Similarity solutions have been obtained for the governing equations of the inner and outer near-wakes. Limited comparisons with experiments for a two-dimensional flow show that the variation of the scales and profiles predicted agree reasonably well with experiments.
